U.S. Pat. Nos. 6,467,682; 6,668,525; 6,886,311 and 6,951,530 disclose a carton, a blank for producing a carton, and methods and apparatus for erecting, closing and sealing a carton. The blank for erecting a carton has fold-in panels that include 180° fold lines with a compressed area at each end and a straight slit joining the compressed areas. A carton is erected by moving the blank in a first direction against a stop to form a first set of 90° folds, holding the blank stationary with a suction while pushing the blank in a second direction to form a second set of 90° folds, erecting the carton. A filled carton is closed by advancing it through the central opening of a V-shaped member to increasingly fold the continuous closure panel formed by the carton top panels. The closed carton is sealed by advancing it through a second V-shaped member and into contact with a pivotally supported sealing device. The disclosures of the aforementioned U.S. patents are hereby incorporated by reference.
An example of this known carton blank 30 from which a carton can be erected is shown in FIG. 1. Blank 30 includes a first side panel 32 having a first end edge 34, a second end edge 36, a top edge 38 and a bottom edge 40. End edges 34 and 36 are substantially parallel with each other, while top edge 38 and bottom edge 40 are substantially parallel with each other and substantially perpendicular to edges 34 and 36. Blank 30 further includes a first end panel 42 having a first side edge 44, a second side edge 46, a top edge 48, and a bottom edge 50. Carton blank 30 also includes a second side panel 52 having a first end edge 54, a second end edge 56, a top edge 58, and a bottom edge 60. Carton 30 further includes a second end panel 62 having a first side edge 64, a second side edge 66, a top edge 68, and a bottom edge 70. Edges 46, 54, 56, 64 and 66 are substantially parallel with edge 34, while edges 48, 58, and 68 are extensions of edge 38, and edges 50, 60, and 70 are extensions of edge 40.
Carton blank 30 also includes a first top panel 72 having a first side edge 74, a second side edge 76, a first end edge 78, and a second end edge 80. Edges 74 and 76 are substantially parallel with edge 38, and edges 78 and 80 are extensions of edges 34 and 36, respectively. Carton blank 30 includes a first bottom panel 82 having a first side edge 84, a second side edge 86, a first end edge 88, and a second end edge 90. Edges 84 and 86 are substantially parallel with edge 38, while edges 88 and 90 are extensions of edges 34 and 36, respectively. Carton blank 30 also includes a first fold-in panel 92 having a first end edge 94, a second end edge 96, a first side edge 98, and a second side edge 100. Edges 94 and 96 are extensions of edges 74 and 76, respectively, while edges 98 and 100 are extensions of edges 44 and 46, respectively. Carton blank 30 has a second fold-in panel 102 having a first end edge 104, a second end edge 106, a first side edge 108, and a second side edge 110. Edges 104 and 106 are extensions of edges 84 and 86 respectively, while edges 108 and 110 are extensions of edges 44 and 46, respectively. Carton blank 30 includes a second top panel 112 having a first side edge 114, a second side edge 116, a first end edge 118, and a second end edge 120. Edges 114 and 116 are extensions of edges 94 and 96, respectively, while edges 118 and 120 are extensions of edges 54 and 56, respectively. Carton blank 30 includes a second bottom panel 122 having a first side edge 124, a second side edge 126, a first end edge 128, and a second end edge 130. Edges 124 and 126 are extensions of edges 104 and 106, respectively, while edges 128 and 130 are extensions of edges 54 and 56, respectively. Carton blank 30 additionally includes a third fold-in panel 132 having a first end edge 134, a second end edge 136, a first side edge 138, and a second side edge 140. Edges 134 and 136 are extensions of edges 114 and 116, respectively, while edges 138 and 140 are extensions of edges 64 and 66, respectively. Carton blank 30 includes a fourth fold-in panel 142 having a first end edge 144, a second end edge 146, a first side edge 148 and a second side edge 150. Edges 144 and 146 are extensions of edges 124 and 126, respectively, while edges 148 and 150 are extensions of edges 64 and 66, respectively.
First end panel 42 extends from first side panel 32, with first side edge 44 of first end panel 42 joined to second side edge 36 of first side panel 32 to define a 90° fold line. Second side panel 52 extends from first end panel 42, with first end edge 54 joined to second side edge 46 to define a 180° fold line. Second end panel 62 extends from second side panel 52, with first side edge 64 joined to second end edge 56 to define a 90° fold line. First top panel 72 extends from first side panel 32, with first side edge 74 joined to top edge 38 to define a 90° fold line. First bottom panel 82 extends from first side panel 32, with first side edge 84 joined to bottom edge 40 to define a 90° fold line. First fold-in panel 92 extends from first end panel 42, with first end edge 94 joined to top edge 48 to define a 90° fold line and with first side edge 98 joined to second end edge 80 to define a 180° fold line. Second fold-in panel 102 extends from first end panel 42, with first end edge 104 joined to bottom edge 50 to define a 90° fold line and with first side edge 108 joined to second end edge 90 to define a 180° fold line. Second top panel 112 extends from second side panel 52, with first side edge 114 joined to top edge 58 to define a 90° fold line and with first end edge 118 joined to second side edge 100 of first fold-in panel 92 to define a 180° fold line. Second bottom panel 122 extends from second side panel 52, with first side edge 124 joined to bottom edge 60 to define a 90° fold line and with first end edge 128 joined to second side edge 110 of second fold-in panel 102 to define a 180° fold line. Third fold-in panel 132 extends from second end panel 62, with first end edge 134 joined to top edge 68 to define a 90° fold line and with first side edge 138 joined to second end edge 120 of top panel 112 to define a 180° fold line. Fourth fold-in panel 142 extends from second end panel 62, with first end edge 144 joined to bottom edge 70 to define a 90° fold line and with first side edge 148 joined to second end edge 130 of bottom panel 122 to define a 180° fold line.
Each fold-in panel 92, 102, 132, and 142 includes a pair of 180° fold lines 152 which extend from a point on the second end edge 96, 106, 136, 146, of the respective panel substantially midway between the first and second side edges of such panel to respective ones of points at the intersections of the first end edge 94, 104, 134, 144 of the respective panel and the first and second side edges of such panel. The carton blank 30 in the example also includes a sealing strip 154 extending from third fold-in panel 132, second end panel 62, and fourth fold-in panel 142 as depicted in FIG. 1. Sealing strip 154 includes fold lines which are extensions of the 90° fold lines defined by edges 68 and 134 and edges 70 and 144. After carton blank 30 has been manufactured, it is folded 180° on the fold line defined by edges 46, 54, 100, 110, 118, and 128, and sealing strip 154 is sealed to panels 72, 32, and 82, forming the folded carton blank as depicted in FIG. 15 of the aforementioned U.S. patents. Alternatively, sealing strip 154 can be omitted, and panels 132, 62, and 142 sealed to panels 72, 32, and 82 by other means such as a sealing tape. Further, instead of making the folded carton blank in one piece, it can be made in two pieces which are then sealed together, as discussed below with regard to FIG. 11.
FIGS. 2-5 show the form of the 180° fold lines of the known carton blank. Each 180° fold line includes first and second compressed areas 156 which extend from opposite ends of the 180° fold line for a distance of about two inches and which are joined by a straight slit 158. Each compressed area 156 is preferably oval in shape with a maximum width of from about ⅜ inch to about ½ inch for standard packing carton corrugated panels. As can be seen in FIG. 3, each compressed area 156 extends into the material of carton blank 30 a substantial distance, while leaving the adjacent panel portions joined. A protrusion 160 extends from the undersurface of carton blank 30, substantially along the center line of each compressed area 156 to define a fold line. As can be seen in FIG. 4, each slit 158 extends through carton blank 30.
FIG. 5 illustrates the manner in which carton blank 30 can be folded 180° as a result of the 180° fold lines formed by compressed areas 156 and slits 158. As can be seen in FIG. 5, as a result of compressed areas 156, the 180° fold is readily made without unduly stressing the carton blank material.
FIGS. 6-10 illustrate the manner in which a carton 162 formed from carton blank 30 can be closed after the carton has been erected and filled. In FIG. 6, carton 162 is illustrated with top panels 72 and 112 and first and second fold-in panels 92 and 132 extending upwardly from their corresponding side panels and end panels together forming a continuous closure panel. FIG. 7 illustrates carton 162 when fold-in panels 92 and 132 are initially folded in on 180° fold lines 152. Top panels 72 and 112 are folded partially together. FIG. 8 depicts carton 162 with the fold-in panels 92 and 132 further folded in and with top panels 72 and 112 folded closer together. FIG. 9 illustrates carton 162 full closed. FIG. 10 shows the closed carton 162 with top panels 72 and 112 sealed together, by a sealing tape 164. Carton 162 can be closed and sealed with the method and apparatus disclosed in the aforementioned U.S. patents or, if desired, carton 162 can be closed and sealed, as well as erected, manually. Manual erecting and closing of carton 162 can be done rapidly by simply pressing on any one of the bottom panels to erect the carton and any one of the top panels to close the carton. Pressing on any one of the bottom panels or of the top panels causes all of the bottom panels or the top panels to fold inwardly, closing the bottom or the top.
Instead of the single piece carton blank 30 of FIG. 1, the carton blank can be formed of two blanks 169 as illustrated in FIG. 11. The two blanks 169 are then positioned one over the other, with one rotated 180° with respect to the other, and the sealing strip of each blank is sealed to the other blank. This construction provides a carton blank 30 just as illustrated in FIG. 15 of the aforesaid U.S. patents.
FIG. 12 depicts another form of carton 162b having a strip 212 of sealing tape affixed to top panel 112 so that when top panels 72 and 112 are closed, the strip will adhere to panel 72, sealing the carton. With this feature, a sealing apparatus is not necessary.
It has been found that the top and bottom panels of cartons erected from these known carton blanks, when closed, have a tendency to spring open from their closed position. There is a need for an improved carton of the above-described type, and an improved carton blank for erecting the carton, which avoids this drawback of the known carton blank and carton.